In the multiple pictures displayed in a video conference, an image located at a specific position in a certain sub-picture can only be amplified by remotely controlling the camera of the terminal corresponding to the sub-picture. For example, the camera is first remotely controlled to face a region of interest and then remotely controlled to zoom in or out on the image to realize this amplification, however, amplifying an image in this way has a problem that the image generated by the terminal at each conference site is affected after the camera of the terminal corresponding to a sub-picture is zoomed.
In a video conference, each terminal can define the number of pictures and a terminal permitted to select and watch a single-picture image by itself. Except for these basic operations, existing technologies make no achievements in enabling each conference terminal to control the definition of a sub-picture selected from multiple pictures for watching or to move a region of interest freely.